Pass-through bulkhead seal fitting

ABSTRACT

Examples disclosed herein generally relate to a pass-through bulkhead seal fitting for use in the aircraft industry. In one example, a pass-through bulkhead seal fitting includes a male fitting comprising a tubular body that is separable to receive existing wiring, and a nut that is separable to receive existing wiring and being rotatable in a single direction relative to a longitudinal axis of the male fitting.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is a continuation of U.S. application Ser. No.14/997,074, filed Jan. 15, 2016. The entire contents of the foregoingapplications are incorporated by reference into the present application.

BACKGROUND

The aircraft industry utilizes flight tests to acquire data to evaluatethe aerodynamic flight characteristics of the vehicle and/or validatethe design and capabilities of the vehicle. During these tests, wiringfor testing the aircraft needs to be connected and disconnected throughbulkheads and/or frames (e.g., a dividing wall or barrier betweencompartments in an aircraft, or other vehicle) using fittings thatprotect wiring as well as maintaining pressurization of the aircraft.The disconnection requires removal of a fitting from the bulkhead orframe, and the wiring. Connection requires installation of a fittingabout the wiring and insertion into the bulkhead or frame. Conventionalfittings require multiple spacers to account for differences inthickness of the bulkhead or frame, and a metal locking ring is utilizedto lock the fitting in place. The typical fittings require specializedtooling for installation or disconnection, which is time consuming.

What is needed is a method and apparatus that simplifies theinstallation or disconnection process of a pass-through fitting.

SUMMARY

Examples disclosed herein generally relate to pass-through bulkhead sealfittings for use in the aircraft industry. In one example, apass-through bulkhead seal fitting includes a male portion comprising atubular body that is separable to receive existing wiring, and a nutthat is separable to receive existing wiring and being rotatable in asingle direction relative to a longitudinal axis of the male portion.

In another example, a pass-through bulkhead seal fitting includes a maleportion comprising a tubular body and having a plurality of sealant exitports formed in a radial direction relative to a longitudinal axis ofthe male portion through an inner surface of the body to an outersurface of the body, and a separable nut portion that is rotatable in asingle direction relative to the longitudinal axis of the male portion.

In another example, a pass-through bulkhead seal fitting includes a maleportion comprising a tubular multi-piece body, and a separablemulti-piece nut that is rotatable in a first direction relative to thelongitudinal axis of the male portion and having one or more detentsformed thereon that prevents rotation of the nut in a second directionopposite to the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toexamples, some of which are illustrated in the appended drawings. It isto be noted, however, that the appended drawings illustrate only typicalexamples of this disclosure and are therefore not to be consideredlimiting of its scope, for the disclosure may admit to other equallyeffective examples.

FIG. 1 is an exploded isometric view of a pass-through bulkhead sealfitting.

FIG. 2A is an isometric top view of the male fitting and the multi-piecenut of FIG. 1, each in an assembled state.

FIG. 2B is an isometric bottom view of the male fitting and themulti-piece nut of FIG. 1, each in an assembled state.

FIG. 3 is an isometric view of the pass-through bulkhead seal fittingfully assembled.

FIG. 4 is a cross-sectional view of the pass-through bulkhead sealfitting along lines 4-4 of FIG. 3.

FIG. 5 is a cross-sectional view of the pass-through bulkhead sealfitting along lines 5-5 of FIG. 3.

FIG. 6A and FIG. 6B are side cross-sectional views of the pass-throughbulkhead seal fitting along lines 6A-6A and 6B-6B of FIG. 3,respectively, with the addition of existing wiring and a barrier.

FIG. 7 is a side cross-sectional view of the pass-through bulkhead sealfitting similar to the view shown in FIG. 6A, with the addition of asealant.

To facilitate understanding, common words have been used, wherepossible, to designate identical elements that are common to thefigures. It is contemplated that elements disclosed in one example maybe beneficially utilized on other examples without specific recitation.

DETAILED DESCRIPTION

FIG. 1 is an exploded isometric view of a pass-through bulkhead sealfitting 100. The pass-through bulkhead seal fitting 100 includes a malefitting 102 and a multi-piece nut 104. The male fitting 102 includes atubular multi-piece body 105 having multiple portions, shown as a firstportion 106 and a second portion 108. Each of the first portion 106 andthe second portion 108 may be halves of the multi-piece body 105. Thefirst portion 106 and the second portion 108 are configured to mate atsides 110 thereof to form the male fitting 102 that may be insertedthrough a bulkhead or frame (e.g., a dividing wall or barrier betweencompartments in an aircraft, or other vehicle (not shown)). In someexamples, the sides 110 may include indexing features, such as aprotruding tab 112 that is received in a depression 114 when the firstportion 106 and the second portion 108 are brought into proximity toeach other. When the first portion 106 and the second portion 108 areseparated as shown, the male fitting 102 may be disposed about existingwiring (not shown) without the need to disconnect and reconnect thewiring.

The multi-piece nut 104 also includes multiple portions, shown as afirst portion 116 and a second portion 118. Each of the first portion116 and the second portion 118 may be halves of the multi-piece nut 104.The first portion 116 and the second portion 118 are configured to mateat sides 120 thereof to form the multi-piece nut 104. In some examples,the sides 120 may include indexing features, such as a protruding tab122 that is received in a depression 124 when the first portion 116 andthe second portion 118 are brought into proximity to each other. Whenthe first portion 116 and the second portion 118 are separated as shown,the multi-piece nut 104 may be disposed about existing wiring (notshown) without the need to disconnect and reconnect the wiring.

When the sides 120 of the first portion 116 and the second portion 118are brought into contact with each other, the multi-piece nut 104 may becoupled to the male fitting 102 (when the sides 110 of the first portion106 and the second portion 108 are brought into contact with eachother).

In some examples, the multi-piece nut 104 includes one or more interlockor fastener devices 125, shown as a clip 126 that releasably mates witha retainer opening 128. Each of the one or more fastener devices 125 maybe utilized to fix the first portion 116 and the second portion 118 toeach other. The clips 126 are biased radially outward (in the Xdirection) such that the first portion 116 and the second portion 118are fixed to each other and will not separate in a radial direction (inthe Y direction). An angled land 133 may be provided on the clip 126 tofacilitate insertion of the clip 126 into the retainer opening 128 whenpressure is applied to the first portion 116 and the second portion 118(in the Y direction). The fastener device 125 is more clearly shown inFIG. 5.

However, if the first portion 116 and the second portion 118 of themulti-piece nut 104 need to be separated, one or both of the clips 126may be pushed inward (in the X direction) such that a shoulder 134 ofthe clips 126 (only one is shown on the second portion 118) clears anexternal wall 137 of the retainer opening 128 (only one is shown on thefirst portion 116). Once at least one of the shoulders 134 clears arespective wall 137, one of the first portion 116 or the second portion118 opens with respect to each other similar to a clamshell allowing themulti-piece nut 104 to be removed from the male fitting 102.Alternatively, the first portion 116 (or the second portion 118)entirely separates from the second portion 118 (or the first portion116) simultaneously or substantially simultaneously.

Both of the male fitting 102 and the multi-piece nut 104 includesthreads, shown as threads 130 and threads 132, respectively. The threads130 on the first portion 106 align with the threads 130 on the secondportion 108 when the respective portions are in proximity with eachother. Likewise, the threads 132 on the first portion 116 align with thethreads 132 on the second portion 118 when the respective portions arein proximity with each other. Each of the first portion 106 and thesecond portion 108 of the male fitting 102 includes a radially extendingflange 136 that may act as a stop against a bulkhead or frame (notshown).

Each of the male fitting 102 and the multi-piece nut 104 may be formedfrom the same or different materials which includes polymer materials,such as thermoplastic materials, for example, polyetherimide (PEI),polyetheretherketone (PEEK), or combinations thereof. The respectiveportions of the male fitting 102 and the multi-piece nut 104 may bemachined, molded, extruded, formed by three dimensional printingtechniques, or other suitable manufacturing method.

FIGS. 2A and 2B are isometric views of the pass-through bulkhead sealfitting 100 of FIG. 1 wherein the male fitting 102 and the multi-piecenut 104 are assembled (via bringing the respective portions of the malefitting 102 and the multi-piece nut 104 into contact). FIG. 2A is anisometric top view of the male fitting 102 and the multi-piece nut 104.FIG. 2B is an isometric bottom view of the male fitting 102 and themulti-piece nut 104.

When the portions of the male fitting 102 are assembled as shown, avolume 200 is formed within the male fitting 102 which may be used tohouse existing wiring (not shown). A surface 205 of the radiallyextending flange 136 (shown in FIG. 2B) is configured to contactportions of a first surface 212 of a barrier 210 (a portion is shown inFIG. 2A), which may be a bulkhead or frame. The barrier 210 includes anopening formed therethrough (not shown) which is sized to receive anouter diameter 215 of the male fitting 102. A surface 220 of themulti-piece nut 104 is adapted to contact an opposing surface 218 of thebarrier 210 during installation. Installation includes rotating the malefitting 102 and the multi-piece nut 104 relative to each other about alongitudinal axis 225 of the pass-through bulkhead seal fitting 100.

The male fitting 102 also includes a plurality of ridges, such as raisedfeatures 230, disposed along an outer peripheral surface 235 of thefirst portion 116 and the second portion 118. In one example, the raisedfeatures 230 are oriented along the longitudinal axis 225. At least aportion of the raised features 230 interface with one or more detents240 disposed on the multi-piece nut 104 (shown in FIG. 2A). The raisedfeatures 230 and the detents 240 comprise an anti-rotation feature(described in more detail below in FIG. 4). The detents 240 may berelatively inflexible and a recessed groove 245 may be formed in theouter peripheral surface 235 of the first portion 116 and the secondportion 118 to facilitate passage of the detents 240 when themulti-piece nut 104 is positioned relative to the male fitting 102 alongthe longitudinal axis 225. The recessed grooves 245 may be utilized as achannel providing a space between outer surfaces of the recessed grooves245 that is less than or equal to an inside dimension 250 of the detents240 (shown in FIG. 2B). The space between the recessed grooves 245 isless than the outer diameter 215 of the male fitting 102 and, duringcoupling of the multi-piece nut 104 to the male fitting 102, the detents240 may be aligned with the recessed grooves 245. The space providedbetween the recessed grooves 245 allows the multi-piece nut 104 tocircumscribe the outer peripheral surface 235 of the first portion 116and the second portion 118 with little or no contact between the detents240 and the outer peripheral surface 235 of the first portion 116 andthe second portion 118. However, when the threads 130 of the malefitting 102 interface with the threads 132 of the multi-piece nut 104,the detents 240 interact with the raised features 230 to providerotation in a single direction and prevent rotation in a directionopposing the single direction. The single direction may depend on thedirection of the threads 130, 132 but, in one example, the multi-piecenut 104 may be rotated clockwise relative to the male fitting 102 andcounter-clockwise rotation is prevented by the detents 240 and theraised features 230.

FIG. 3 is an isometric view of the pass-through bulkhead seal fitting100 fully assembled. As shown, the multi-piece nut 104 is coupled to themale fitting 102 and a barrier (shown in FIG. 2A) may be disposedbetween the surface 205 of the radially extending flange 136 and thesurface 220 of the multi-piece nut 104. The pass-through bulkhead sealfitting 100 as described herein provides an adjustable barrier space 300formed between the surface 205 of the radially extending flange 136 andthe surface 220 of the multi-piece nut 104. The adjustable barrier space300 accommodates multiple barriers with different thicknesses allowingthe pass-through bulkhead seal fitting 100 to be utilized with differentbulkheads or frames. Further, the relative rotation between the malefitting 102 and the multi-piece nut 104 provides tightening against thebarrier without the use of spacers or a specialized tool as is typicalwith conventional fittings. For example, the relative rotation of themale fitting 102 and the multi-piece nut 104 may be facilitated by handwithout the use of other tooling. However, if additional torque isneeded, one or more flats 305 are provided on the multi-piece nut 104 tofacilitate use with a standard wrench.

FIG. 4 is a cross-sectional view of the pass-through bulkhead sealfitting 100 along lines 4-4 of FIG. 3. The detents 240 are showninterfacing with the raised features 230 to provide an anti-rotationfeature 400. The anti-rotation feature 400 allows rotation of themulti-piece nut 104 in a first direction 405 while preventing rotationof the multi-piece nut 104 in a second direction 410. Alternatively, theanti-rotation feature 400 may allow rotation of the male fitting 102 inthe second direction 410 while preventing rotation of the male fitting102 in the first direction 405. The detents 240 may include a point 415that interfaces with a depression 420 of the raised features 230. Thedepressions 420 may include an angle that allows the point 415 toadvance in a single direction.

FIG. 5 is a cross-sectional view of the pass-through bulkhead sealfitting 100 along lines 5-5 of FIG. 3 showing the fastener device 125described in FIGS. 2A and 2B. The fastener devices 125 include the clips126 and the retainer opening 128 which couple the first portion 116 andthe second portion 118 together. However, if the first portion 116 andthe second portion 118 need to be separated, one or both of the clips126 may be pushed radially inward (in the X direction) by hand, and theshoulder 134 of the clips 126 clears the external wall 137 of theretainer opening 128 allowing one or both of the first portion 116 andthe second portion 118 to move away from each other (with slightly lesspressure on the clips 126 in the Y direction to push the clips 126through the retainer openings 128).

FIGS. 6A and 6B are side cross-sectional views of the pass-throughbulkhead seal fitting 100 along lines 6A-6A and 6B-6B of FIG. 3,respectively, with the addition of existing wiring 600 and a barrier210. The existing wiring 600 may be disposed through an opening 605 ofthe barrier 210. A first end 610 of the pass-through bulkhead sealfitting 100 may be disposed in a pressurized environment HP while asecond end of the pass-through bulkhead seal fitting 100 may be disposedin a lower pressure environment LP.

To install the pass-through bulkhead seal fitting 100, the male fitting102 may be separated into the first portion 106 and the second portion108. The portions may then be positioned about the existing wiring 600and inserted through the opening 605 of the barrier 210. The portions106 and 108 may be placed in proximity about the existing wiring 600 toform the male fitting 102. Then, the multi-piece nut 104 that isseparated into the first portion 116 and the second portion 118 may bepositioned about the existing wiring 600. The first portion 116 and thesecond portion 118 may be joined by the fastener devices 125 about theexisting wiring 600. The multi-piece nut 104 may be positioned where thedetents 240 pass the outer peripheral surface 235 of the first portion116 and the second portion 118 in the recessed grooves 245 and movedtoward the radially extending flange 136 of the male fitting 102. Oncethe threads 130, 132 interface, one or both of the male fitting 102 andthe multi-piece nut 104 may be rotated relative to each other to fix thepass-through bulkhead seal fitting 100 to the barrier 210. The rotationmay be accomplished by hand to capture the barrier 210 between the malefitting 102 and the multi-piece nut 104. If additional torque is needed,the flats 305 (shown in FIG. 3) may be used. The anti-rotation feature400 prevents the multi-piece nut 104 from backing-off the male fitting102.

The pass-through bulkhead seal fitting 100 is also configured to receivea sealant for a complete pressure seal. The sealant application processwill be described using FIGS. 6A, 6B and 7.

As described above, the male fitting 102 includes the outer peripheralsurface 235 on the second end 615 thereof. Likewise, the first end 610of the male fitting 102 includes an outer peripheral surface 620. Thesurfaces 235 and 620 may be utilized as a surface for applying anadhesive member or material, such as tape 625. The tape 625 may bedisposed about the surfaces 235 and 620 as well as the existing wiring600 to form a volume 630. The tape 625 may be used to bind the existingwiring 600 tightly at the first end 610 and the second end 615 of themale fitting 102. The volume 630 is formed by a boundary comprisinginterior surfaces of the tape 625, interior surfaces of the male fitting102 and the bound wiring.

The male fitting 102 also includes a sealant distribution feature 635that includes first openings 640 and second openings 645. The firstopenings 640 are in fluid communication with the volume 630 and thesecond openings 645 are in fluid communication with an annular channel650 formed in the surface 205 of the radially extending flange 136. Thesecond openings 645 may be formed in an annular depression 655 of themale fitting 102. The first openings 640 are formed in the outerperipheral surface 620 of the male fitting 102. The first openings 640also include a flared opening 660 having an opening dimension 665 (whichmay be a diameter) that is greater than a dimension 670 (which may be adiameter) of the first opening 640. The flared opening 660 provides avolume 675 between interior surfaces thereof and the tape 625 that maybe utilized as a gauge for determining the extent of sealant in thevolume 630 as will be explained in greater detail in FIG. 7. While thereare two flared openings 660 and two first openings 640 shown in FIG. 6A,the number of flared openings 660 and first openings 640 may be greaterthan two. The radially extending flange 136 also includes one or morethird openings 680 that are in fluid communication with the annularchannel 650. The third openings 680 may be utilized to determine theextent of sealant in the annular channel 650 as will be explained ingreater detail in FIG. 7. While there are two third openings 680 shownin FIG. 6B, the number of third openings 680 may be greater than two.

FIG. 7 is a side cross-sectional view of the pass-through bulkhead sealfitting 100 similar to the view shown in FIG. 6A, with the addition of asealant 700. The sealant 700 may be a commercially available sealanttypically used in the aircraft industry for pass-through fittings. Thesealant 700 may be applied via a nozzle 705 to the volume 630 containedat least partially within the male fitting 102 and the tape 625. Thesealant 700 may be applied as a liquid at a relatively low viscosity andmay cure to a solid or near solid after application.

The sealant 700 may be applied through the nozzle 705 by piercing thetape 625 adjacent to one of the flared openings 660 to form an opening710 that is in fluid communication with the volume 630. The sealant 700should substantially fill the volume 630 including any spaces within oradjacent to the existing wiring 600. Additionally, the sealant 700should be provided in the annular channel 650 to form a seal between thesurface 205 of the radially extending flange 136 and the surface 212 ofthe barrier 210. The sealant 700 flows through the second openings 645(hidden by the sealant 700 in FIG. 7 but shown in FIG. 6A) into theannular channel 650 in order to provide the sealant 700 to the annularchannel 650.

To determine that the volume 630 is suitably filled with the sealant700, bulges 715 (only one is shown in this view) are formed within therespective volumes 675 (only one is shown in this view). The bulges 715may be slight protrusions in the tape 625 that extend radially outwardand provide a visual indication of the level of sealant 700 within thevolume 630. A portion of the first openings 640 not used to insert thenozzle 705 may be referred to as sealant exit ports that provide anindication of the sealant level within the volume 630. Additionally, thelevel of sealant 700 within the annular channel 650 may be determinedwhen sealant 700 is within, or exits, the third openings 680 of theradially extending flange 136. The third openings 680 may be referred toas sealant exit ports. The sealant 700 may then harden after a few hoursto provide a seal between at the opening in the barrier 210, whicheffectively seals the pressurized environment HP from the lower pressureenvironment LP. The sealant 700 that resides in the annular depression655 (shown in FIGS. 6A and 6B) may further secure the pass-throughbulkhead seal fitting 100 to the bound existing wiring 600 and thusprevent movement therebetween.

The pass-through bulkhead seal fitting 100 as described herein provideseasier and quicker installation and removal as compared to conventionalfittings. The pass-through bulkhead seal fitting 100 as described hereinreduces parts from the conventional fittings (up to nine loose parts) tofour parts (the first portion 106 and the second portion 108 of the malefitting 102, and the first portion 116 and the second portion 118 of themulti-piece nut 104). It is estimated that the install time for thepass-through bulkhead seal fitting 100 is reduced by about 4 minutes ascompared to the conventional fitting install time. There are hundreds ofthese pass-through connections on a typical aircraft and several hoursare saved using the pass-through bulkhead seal fitting 100 as describedherein. Further, as the pass-through connections are numerous on anaircraft, the reduced part count saves weight. Additionally, thepass-through bulkhead seal fitting 100 requires no specialized toolingas is required on the conventional fittings.

What is claimed is:
 1. A method for installing a pass-through bulkhead seal fitting, comprising: disposing a first portion of a male fitting around one or more wires; disposing a second portion of the male fitting around the one or more wires; joining the first portion of the male fitting to the second portion of the male fitting such that the one more wires run axially through the joined first portion of the male fitting and the second portion of the male fitting; disposing a first portion of a multi-piece nut around the one or more wires; disposing a second portion of a multi-piece nut around the one or more wires; joining the first portion of the multi-piece nut to the second portion of the multi-piece nut; and coupling the joined first portion of the multi-piece nut and the second portion of the multi-piece nut onto the joined first portion of the male fitting and the second portion of the male fitting, the coupling comprising rotating, in a first direction, the joined first portion of the multi-piece nut and the second portion of the multi-piece nut relative to the joined first portion of the male fitting and the second portion of the male fitting, wherein rotation of the joined first portion of the multi-piece nut and the second portion of the multi-piece nut is prevented in a second direction opposite the first direction.
 2. The method of claim 1, further comprising inserting the joined first portion of the male fitting and the second portion of the male fitting through a hole in a bulkhead.
 3. The method of claim 2, wherein the joined first portion of the male fitting and the second portion of the male fitting include a radially extending flange, and wherein the radially-extending flange is positioned on a first side of the bulkhead.
 4. The method of claim 3, wherein the joined first portion of the multi-piece nut and the second portion of the multi-piece nut are positioned on a second side of the bulkhead.
 5. The method of claim 4, wherein the coupling comprises contacting the first side of the bulkhead with the radially extending flange, and the contacting the second side of the bulkhead with the joined first portion of the multi-piece nut and the second portion of the multi-piece nut.
 6. The method of claim 1, wherein the first portion of the male fitting and the second portion of the male fitting are joined along an axial length thereof.
 7. The method of claim 1, further comprising disposing a sealant within the joined first portion of the male fitting and the second portion of the male fitting.
 8. The method of claim 1, wherein joining the first portion of the male fitting to the second portion of the male fitting comprises aligning indexing features on the first portion of the male fitting to the second portion of the male fitting.
 9. The method of claim 1, wherein joining the first portion of the multi-piece nut to the second portion of the multi-piece nut comprises engaging one or more interlocks of the first portion of the multi-piece nut to the second portion of the multi-piece nuts.
 10. The method of claim 9, wherein the one or more interlocks comprise clips.
 11. The method of claim 1, further comprising engaging a detent that is formed on the first portion of the multi-piece nut with a ridge formed on the first portion of the male fitting.
 12. A method for installing a pass-through bulkhead seal fitting, comprising: disposing a first portion of a male fitting around one or more wires; disposing a second portion of the male fitting around the one or more wires; joining the first portion of the male fitting to the second portion of the male fitting such that the one more wires run axially through the joined first portion of the male fitting and the second portion of the male fitting; inserting the joined first portion of the male fitting and the second portion of the male fitting through an opening formed in a bulkhead; contacting the bulkhead with a radially extending flange of the joined first portion of the male fitting and the second portion of the male fitting; disposing a first portion of a multi-piece nut around the one or more wires; disposing a second portion of a multi-piece nut around the one or more wires; joining the first portion of the multi-piece nut to the second portion of the multi-piece nut by engaging a clip of the first portion of the multi-piece nut with a retainer opening of the second portion of the multi-piece nut; threading the joined first portion of the multi-piece nut and the second portion of the multi-piece nut onto the joined first portion of the male fitting and the second portion of the male fitting, the threading comprising rotating, in a first direction, the joined first portion of the multi-piece nut and the second portion of the multi-piece nut relative to the joined first portion of the male fitting and the second portion of the male fitting, wherein rotation of the joined first portion of the multi-piece nut and the second portion of the multi-piece nut is prevented in a second direction opposite the first direction; and securing the joined first portion of the male fitting and the second portion of the male fitting in the opening formed in the bulkhead.
 13. The method of claim 12, wherein the radially-extending flange is positioned on a first side of the bulkhead.
 14. The method of claim 13, wherein the joined first portion of the multi-piece nut and the second portion of the multi-piece nut are positioned on a second side of the bulkhead.
 15. The method of claim 12, wherein the first portion of the male fitting and the second portion of the male fitting are joined along an axial length thereof.
 16. The method of claim 12, wherein joining the first portion of the multi-piece nut to the second portion of the multi-piece nut comprises engaging one or more interlocks of the first portion of the multi-piece nut to the second portion of the multi-piece nuts.
 17. The method of claim 16, wherein the one or more interlocks comprise clips.
 18. A method for installing a pass-through bulkhead seal fitting, comprising: disposing a first portion of a male fitting around one or more wires; disposing a second portion of the male fitting around the one or more wires; joining the first portion of the male fitting to the second portion of the male fitting such that the one more wires run axially through the joined first portion of the male fitting and the second portion of the male fitting, the joining comprising aligning indexing features on the first portion of the male fitting to the second portion of the male fitting; inserting the joined first portion of the male fitting and the second portion of the male fitting through an opening formed in a bulkhead; disposing a first portion of a multi-piece nut around the one or more wires; disposing a second portion of a multi-piece nut around the one or more wires; joining the first portion of the multi-piece nut to the second portion of the multi-piece nut; threading the joined first portion of the multi-piece nut and the second portion of the multi-piece nut onto the joined first portion of the male fitting and the second portion of the male fitting, the threading comprising rotating, in a first direction, the joined first portion of the multi-piece nut and the second portion of the multi-piece nut relative to the joined first portion of the male fitting and the second portion of the male fitting, wherein rotation of the joined first portion of the multi-piece nut and the second portion of the multi-piece nut is prevented in a second direction opposite the first direction; securing the joined first portion of the male fitting and the second portion of the male fitting in the opening formed in the bulkhead; introducing a sealant into the joined first portion of the male fitting and the second portion of the male fitting while secured in the bulkhead.
 19. The method of claim 18, wherein the first portion of the male fitting and the second portion of the male fitting are joined along an axial length thereof.
 20. The method of claim 19, wherein rotation in the second direction is prevented by a plurality of axial ridges disposed on the joined first portion of the male fitting and the second portion of the male fitting. 